1. Field of the Invention
This invention relates to a sealing system for producing a waterproof seal between a waterproof roofing membrane and the curb surrounding a roof opening. It also relates to roof hatchways employing such a sealing system.
2. Related Art
Modern waterproof roofing membranes are extremely effective in providing a long lasting durable waterproof roof. To apply a roof employing such membranes, rolls of the roofing membrane sheet material are unrolled to cover the surface of a roof to be sealed, and then cut to fit. Adjacent pieces of the membrane are sealed to each other with heat or adhesive to form a perfectly waterproof cover for the roof. Problems are seldom encountered with such roofing membranes in the flat and unobstructed areas of the roof. However, when it is necessary to provide an opening in the roof, such as is required for a scuttle, access hatch, automatic fire vent or skylight, great care must be taken to ensure that the roofing membrane is tightly sealed to the curb wall surrounding the roof opening.
In the unobstructed areas of the roof, adjacent pieces of the roofing membrane can easily be bonded together in flat, wrinkle-free seams. Because these portions of the roof are flat or only moderately inclined, the membrane and seams are fully supported by the underlying roof and by the force of gravity which tends to hold the membrane in position.
However, at the curb surrounding a roof opening, the roofing membrane must be turned around corners and up along the faces of the curb wall to maintain the waterproof seal. On these surfaces, the roofing membrane is not supported and the force of gravity constantly pulls on the roofing membrane, occasionally causing it to slip out of position, ultimately causing leaks. Thus it is necessary to mechanically secure the turned-up edge of the roofing membrane near the top of the curb wall to provide support. This support is also important during installation of the roofing membrane when it is necessary to hold portions of the membrane temporarily in position before final sealing of the membrane seams.
Such mechanical support is presently accomplished by nailing the membrane roofing material at the top of the curb. However, this punctures the membrane material and is often the source of leaks. Also, on the harsh exposed environment of the roof, conventional nails are prone to rusting. Thus, specialized corrosion resistant fasteners are required which are often supplied with the flashing which accompanies a roof hatch. Unfortunately, these loose fasteners are easily lost during shipment and are difficult to distinguish from conventional fasteners, resulting in the substitution of non-corrosion resistant fasteners which corrode and fail.
Accordingly, one object of the present invention is to provide a waterproof sealing system between a roofing membrane and a curb which does not employ loose fasteners. Another object of the invention is to provide a sealing system wherein the spacing of the fasteners is even, providing good support for the membrane along the entire upper edge of the curb. Yet another object of the invention is to provide a reliable, inexpensive and easily installed support for the roofing membrane at the upper edge of the curb. A further object of the invention is to provide a pre-manufactured sealing system of suitable size and shape to be positioned on an existing curb surrounding the perimeter of a roof opening. Still another object of the invention is to provide a roof hatchway integrated with a premanufactured sealing system, appropriate flashing and a curb suitable for positioning around a roof opening.